var express = require('express');
var createError = require('http-errors');
var path = require('path');
var cookieParser = require('cookie-parser');
var logger = require('morgan');
// 1引入代理服务器
const { createProxyMiddleware } = require('http-proxy-middleware');
// 2 配置代理服务器
 const options = {
  target: 'http://127.0.0.1:4000', // target 配置后台服务器的地址
  changeOrigin: true, // 支持跨域
  pathRewrite:{   //路径重写
     '^/api':"/"
  }
}; 

//3 创建代理服务器
const studentServerProxy = createProxyMiddleware(options);

var app = express();

app.use(express.static(path.join(__dirname, 'public')));

//4 注册代理服务器 
//注意： 位置必须在处理静态资源之后，注册其他的中间件之前
//挂载代理服务器
app.use('/', studentServerProxy);

// catch 404 and forward to error handler
app.use(function(req, res, next) {
  next(createError(404));
});

// error handler
app.use(function(err, req, res, next) {
  // set locals, only providing error in development
  res.locals.message = err.message;
  res.locals.error = req.app.get('env') === 'development' ? err : {};

  // render the error page
  res.status(err.status || 500);
  res.render('error');
});

module.exports = app;
